GitHub Advisoryadvisory · npm
GHSA-5wm8-gmm8-39j9 fast-xml-builder allows attribute values with unwanted quotes to bypass malicious or unwanted attributes
HIGH
Official page ↗
- Aliases
- CVE-2026-44665
- Ecosystem
- npm
- Packages
- fast-xml-builder
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- Weaknesses
- CWE-611, CWE-91
- Reviewed
- 2026-05-08
Affected packages
• npm fast-xml-builder: < 1.1.7 → fixed in 1.1.7
Description
Summary
When an input data has quotes in attribute values but process entities is not enabled, it breaks the attribute value into multiple attributes. This gives the room for an attacker to insert unwanted attributes to the XML/HTML.
Detail
Malicious Input
```
{
a: {
"@_attr": '" onClick="alert(1)'
}
}
```
Output
```xml
```
Workarounds
If you're not ignoring attributes then keep processEntities flag true.
Related
Alias · CVE (1)
- CVE-2026-44665 fast-xml-builder builds XML from JSON. vulnerability